I suggest you revisit the subject with your friends, with two key points:

1. Make it clear to them that with "internal monologue" you do not mean an actual audible hallucination

2. Ask them if they EVER have imagined themselves or others saying or asking anything

If they do, which they 100% will unless they lie, then you have ruled out "does not have an internal monologue", the claim is now "does not use his internal monologue as much". You can keep probing them what exactly that means, but it gets washy.

Someone that truly does not have an internal dialogue could not do the most basic daily tasks. A person could grab a cookie from the table when they feel like it (oh, :cookie-emoji:!), but they cannot put on their shoes, grab their wallet and keys, look in the mirror to adjust their hair, go to the supermarket, to buy cookies. If there were another hidden code that can express all huge mental state pulled by "buy cookies", by now we would at least have an idea that it exists underneath. We must also ask, why would we translate this constantly into language, if the mental state is already there? Translation costs processing power and slows down. So why are these "no internal monologue" people not geniuses?

I have no doubt that there is a spectrum, on that I agree with you. But the spectrum is "how present is (or how aware is the person of-) the internal monologue". E.g. some people have ADHD, others never get anxiety at all. "No internal monologue" is not one end of the spectrum for functioning adults.

The cat actually proves my point. A cat can sit for a long time before a mouse-hole, or it can hide to jumpscare his brother cat, and so on. So to a very small degree there is something that let's it process ("understand") very basic and near-future event and action-reactions. However, a cat could not possibly go to the supermarket to buy food, obviating anatomical obstacles, because: it has no language and therefore cannot make a complex mental model. Fun fact: whenever animals (apes, birds) have been taught language, they never ask questions (some claim they did, but if you dig in you'll see that the interpretation is extremely dubious).

▲ godelski 10 hours ago | parent [-]

  > 1. Make it clear to them that with "internal monologue" you do not mean an actual audible hallucination

What do you mean? I hear my voice in my head. I can differentiate this from a voice outside my head, but yes, I do "hear" it.

And yes, this has been discussed in depth. It was like literally the first thing...

But no, they do not have conversations in their heads like I do. They do not use words as their medium. I have no doubt that their experience is different from mine.

  > 2. Ask them if they EVER have imagined themselves or others saying or asking anything

This is an orthogonal point. Yes, they have imagined normal interactions. But frequently those imaginary conversations do not use words.

  > The cat actually proves my point.

Idk man, I think you should get a pet. My cat communicates with me all the time. But she has no language.

  > Fun fact: whenever animals (apes, birds) have been taught language, they never ask questions (some claim they did, but if you dig in you'll see that the interpretation is extremely dubious).

To be clear, I'm not saying my cat's intelligence is anywhere near ours. She can do tricks and is "smart for a cat" but I'm not even convinced she's as intelligent as the various wild corvids I feed.

	▲	the_gipsy 9 hours ago \| parent [-]
		It's pretty self explanatory: there's actual voice heard with your ears, there's the internal monologue, and then there's a hallucination. > Yes, they have imagined normal interactions. But frequently those imaginary conversations do not use words. And you did not dig in deeper? How exactly do you imagine a conversation without words?